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THE language of ice in Antarctica gains clarity at about 500
feet up. It's from here, glimpsed through the just-open tailgate of
a low-flying aircraft, that the nuance of its vocabulary, baffling
in the scientific reports, may be heard.

The soft fragility of the floes, a translucent crust over the
bays. The booming magnificence of a glacier, its echo extending to
an ice shelf that calves icebergs into the sea. Isolated islands of
ice, their ballast glowing emerald green under the water, pushing
loudly into the subdued scatter of pack ice. Screaming crevasses
fracturing the ice sheet, revealing unfathomable blue in its
depths.

The dynamics of the forces creating all this continues to
confound scientists, who are now scrambling to translate and
explain the language of ice even as it seems to find new and
troubling expressions. Increasing amounts of ice mass have been
lost from West Antarctica and the Antarctic Peninsula over the past
decade, according to accumulating research, the latest of it
published last week in Nature Geoscience. The same research
found that the ice mass over which we are flying  part of
East Antarctica  has stayed roughly stable.

We've travelled past the Vanderford Glacier and another hour
north-east of Casey station to Bunger Hills, where Australian
Antarctic Division field training officer Rob Brittle will check on
supplies and equipment in rarely used field huts, and pilot John
Lee-Steere needs to unload some fuel reserves.

With the arrival of more scientific teams and support crews via
the new Airbus flights from Australia, there's increasing
small-aircraft traffic between Australia's three research stations.
Bunger Hills  between Casey and Davis, and with a smooth bed
of solid sea ice to land on  provides a handy stopover point
for fuel if required.

For us, the trip provides perspective on the many manifestations
of ice that increasingly preoccupy scientific journals and climate
change forums.

"On the east, as best we can tell, the amount of ice discharged
into the sea and the amount of snow falling is roughly in balance,"
says Tas van Ommen, glaciologist and principal research scientist
at AAD.

"We haven't seen any clear sign of change, unlike the west,
where there is clearly ongoing ice loss that is definitely attached
to global warming, well outside the natural variability.

"In both cases, east and west, what concerns us is that we don't
have a good understanding of what we call the basal processes
 what's happening at the base of the ice sheet, the interface
of the ice and the land or ocean beneath. And what we don't capture
well in our climate models could lead to more rapid loss of ice
than we've been predicting till now."

The absence of that knowledge underwrote one of the most
controversial portions of last year's landmark International Panel
on Climate Change report, which pulled back its previous upper
projections of estimated sea level rise from ice melt to 59
centimetres from 88 centimetres by the end of this century. But it
did so with the caveat that the rise may be 20 centimetres more due
to additional loss from Antarctica and Greenland due to unknown
dynamic processes, adding that "larger values cannot be
excluded".

The urgent task confronting scientists is to reduce the window
of that too-large factor of unknown variability, says Dr van Ommen,
which requires coming to grips with the invisible complexities of
the relationship of ice and water and bedrock.

In the east, while there is not much change in the ice sheet
mass itself, there is concern about areas like the Totten Glacier
(south of Casey). Research by his colleague Dr Neal Young has
tracked a loss of 10 metres from the altitude of the Totten over a
16 year period. That loss is evident in satellite data where the
changes to the Totten show up starkly against the more moderate
story of the eastern ice  mimicking the more extreme
situation in the west and along the tail of the Antarctic
Peninsula.

The British research published last week estimated a loss of 132
billion tonnes of ice in 2006 from West Antarctica, up from 83
billion tonnes in 1996, and a loss of about 60 billion tonnes in
2006 from the Antarctic Peninsula.

Antarctica's ice, they concluded, is much more complex than
scientists had previously appreciated. And while they are primarily
preoccupied with understanding the changes apparent now in the
west, they signal that the stability of the eastern icescape
unfolding beneath our aircraft may not be as it seems. "Thinning of
its potentially vulnerable marine sectors suggests this may change
in the near future," the report concludes.

Tiny, solitary black dots race across the icebergs below us
 penguins, alarmed at the appearance of our big noisy bird.
Larger shapes sit unperturbed  seals baking in the constant
sun. Sudden ripples on the still surface water betray a pod of
whales.

But here biology is merely a bit player in the scene. The
biggest character is heard in the infinite, unreadable, mute
symphony of the ice.

Jo Chandler and Age photographer Angela Wylie are
visiting Casey on a fellowship from the Australian Antarctic
Division.

470310Angela Wyliehttp://www.theage.com.au/multimedia/newiceage/<b>Multimedia</b> The new ice agetext/html-externalhttp://www.theage.com.au/multimedia/newiceage/<b>Multimedia</b> The new ice agetext/html-external